[Elecraft] K3 Sub Receiver and protecting the Sub RX input

[Harry Yingst via Elecraft]

I ordered the sub receiver and in the conversation with Elecraft I was informed that it is good idea to build a device that would short the dedicated RX antenna to ground to protect it during transmit.
The simple way would be a relay but I'd rather not hear a relay click with each transmission.
I was wondering what others are using to accomplish this.

Thank you